Humeral arthroplasty

ABSTRACT

Arthroplasty components include an articular surface and a bone-facing surface. The bone-facing surface includes a concave arrangement of planar surfaces which converge as they approach a middle portion of the articular surface. Instruments and implantation methods are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of:

U.S. patent application Ser. No. 15/629,182, filed Jun. 21, 2017,entitled HUMERAL ARTHROPLASTY, Attorney's docket no. CAO-2 CON2, whichis pending.

U.S. patent application Ser. No. 15/629,182 is a continuation of:

U.S. patent application Ser. No. 15/042,601, filed Feb. 12, 2016,entitled HUMERAL ARTHROPLASTY, Attorney's docket no. CAO-2 CON1, whichissued as U.S. Pat. No. 9,814,587 on Nov. 14, 2017.

U.S. patent application Ser. No. 15/042,601 is a continuation of:

U.S. patent application Ser. No. 14/069,154, filed Oct. 31, 2013,entitled HUMERAL ARTHROPLASTY, Attorney's docket no. CAO-2, which issuedas U.S. Pat. No. 9,289,306 on Mar. 22, 2016.

U.S. patent application Ser. No. 14/069,154 claims the benefit of:

U.S. Provisional Patent Application No. 61/794,348, filed Mar. 15, 2013,entitled HUMERUS PROSTHETIC COMPONENT WITH MULTIPLE CIRCLES OF A SPHEREDESIGN AND ASSOCIATED INSTRUMENTATION, Attorney's docket no.McHale/Slavin 3858U.002, which is expired.

The above referenced documents are incorporated herein by reference intheir entirety.

BACKGROUND

In total shoulder arthroplasty, a glenoid implant is attached to aprepared glenoid or scapula, and a humeral implant is attached to aprepared humerus. The humeral implant usually includes a convexarticular surface, at a proximal end thereof which engages and movesrelative to a concave articular surface formed in the glenoid implant,although this arrangement is sometimes reversed so that the humeralimplant includes the convex articular surface and the glenoid implantincludes the convex articular surface. The ligaments and muscles of theshoulder surround the implants and maintain the humeral implant againstthe glenoid implant, while at the same time allowing relative movementtherebetween.

Current anatomic prostheses for the proximal humerus generally fall intotwo types: stemmed prostheses and resurfacing prostheses.

Stemmed prostheses are quite common. Stemmed prostheses combine ahemispherical head replacement with a stem which extends into the shaft(diaphysis) of the humerus to anchor the prosthesis. Stemmed prosthesesoften require the removal of the entire hemisphere of humeral head bone,as well as drilling, reaming and/or broaching into the adjacent shaft ofthe humerus to seat the component. The hemispherical head component andstem are typically solid metal and can be of considerable weight.Stemmed prostheses also frequently require the surgeon to place thehumeral head articular bearing surface in a position which is eitherfixed relative to the shaft of the humerus, or has modular adjustableconnection mechanisms allowing partial adjustment between the placementof the hemispherical head component and the stem placed in the shaft ofthe humerus. This may not always match the actual anatomy of thepatient, especially if deformity is present. Although many currentprostheses provide for adjustments such as retroversion, offset, orneck-shaft angle, these adjustments are always limited to some degree,or constrained, by the stem to which the prosthetic humeral head isattached.

Resurfacing prostheses have a hollow hemisphere which rests on top ofthe humeral bone with a solitary peg or post in the humeral head foranchoring stability. Resurfacing prostheses have the advantage ofresting directly on top of the bone of the upper humerus and do not havea stem that extends into the shaft of the humerus. Therefore the surgeonis free to place the prosthesis based on each individual patient'sanatomy. Resurfacing prostheses also do not require the removal of theentire humeral head bone; simply the upper articular end is reshaped toaccept the prosthesis sitting on top. The prosthesis itself acts as asurface cover, and the volume of bone underneath in the hemisphereremains. This preserves more of the patient's bone stock and if revisionsurgery is needed, allows for a much simpler re-operation because theshaft has not yet been violated.

The preservation of bone in the upper humerus with a resurfacingprosthesis may unfortunately become a disadvantage when the surgeonperforms a total shoulder arthroplasty. In this operation, the surgeonalso places a prosthesis into the glenoid cavity of the scapula. Withthe bone of the upper humerus still in the way, access to the glenoidmay be very difficult and placing the glenoid prosthesis properly can bechallenging.

BRIEF DESCRIPTION OF THE DRAWINGS

While examples of the present technology have been shown and describedin detail below, it will be clear to the person skilled in the art thatvariations, changes and modifications may be made without departing fromits scope. As such, that which is set forth in the following descriptionand accompanying drawings is offered by way of illustration only and notas a limitation. The actual scope of the invention is intended to bedefined by the following claims, along with the full range ofequivalents to which such claims are entitled.

Identical reference numerals do not necessarily indicate an identicalstructure. Rather, the same reference numeral may be used to indicate asimilar feature or a feature with similar functionality. Not everyfeature of each example is labeled in every figure in which that exampleappears, in order to keep the figures clear. Similar reference numbers(e.g., those that are identical except for the first numeral) are usedto indicate similar features in different examples.

FIG. 1A is an isometric view of a humeral component; FIG. 1B is a medialview of the humeral component of FIG. 1A; FIG. 1C is a cross sectionalview of the humeral component of FIG. 1A, taken along section line 1C-1Cof FIG. 1E; FIG. 1D is a superior view of the humeral component of FIG.1A; FIG. 1E is a lateral view of the humeral component of FIG. 1A; andFIG. 1F is a cross sectional view of the humeral component of FIG. 1A,taken along section line 1F-1F of FIG. 1E;

FIG. 2A is an isometric view of another humeral component; FIG. 2B is amedial view of the humeral component of FIG. 2A; FIG. 2C is a crosssectional view of the humeral component of FIG. 2A, taken along sectionline 2C-2C of FIG. 2E; FIG. 2D is a superior view of the humeralcomponent of FIG. 2A; FIG. 2E is a lateral view of the humeral componentof FIG. 2A; and FIG. 2F is a cross sectional view of the humeralcomponent of FIG. 2A, taken along section line 2F-2F of FIG. 2E;

FIG. 3A is an isometric view of yet another humeral component; FIG. 3Bis a medial a view of the humeral component of FIG. 3A; FIG. 3C is across sectional view of the humeral component of FIG. 3A, taken alongsection line 3C-3C of FIG. 3E; FIG. 3D is a superior view of the humeralcomponent of FIG. 3A; FIG. 3E is a lateral view of the humeral componentof FIG. 3A; and FIG. 3F is a cross sectional view of the humeralcomponent of FIG. 3A, taken along section line 3F-3F of FIG. 3E;

FIG. 4A is an isometric view of yet another humeral component; and FIG.4B is a lateral view of the humeral component of FIG. 4A;

FIG. 5A is an isometric view of yet another humeral component; and FIG.5B is a lateral view of the humeral component of FIG. 5A;

FIG. 6A is a superior view of yet another humeral component; FIG. 6B isan anterior view of the humeral component of FIG. 6A; FIG. 6C is amedial view of the humeral component of FIG. 6A; FIG. 6D is an isometricview of the humeral component of FIG. 6A; FIG. 6E is an inferior view ofthe humeral component of FIG. 6A; FIG. 6F is a cross sectional view ofthe humeral component of FIG. 6A, taken along section line 6F-6F of FIG.6C, with superimposed cross sectional profiles of two other size humeralcomponents; FIG. 6G is a cross sectional view of the humeral componentof FIG. 6A, taken along section line 6G-6G of FIG. 6C, with superimposedcross sectional profiles of two other size humeral components; FIG. 6His a front left perspective view of the humeral component of FIG. 6A;FIG. 6I is a back left perspective view of the humeral component of FIG.6A; FIG. 6J is a back view of the humeral component of FIG. 6A; FIG. 6Kis a front view of the humeral component of FIG. 6A; FIG. 6L is a rightside view of the humeral component of FIG. 6A; FIG. 6M is a left sideview of the humeral component of FIG. 6A; FIG. 6N is a top view of thehumeral component of FIG. 6A; FIG. 6O is a bottom view of the humeralcomponent of FIG. 6A; FIG. 6P is a cross sectional view of a leftportion of the humeral component of FIG. 6A taken along line 6P-6P ofFIG. 6J; and FIG. 6Q is a cross sectional view of a bottom portion ofthe humeral component of FIG. 6A taken along line 6Q-6Q of FIG. 6J;

FIG. 7A is an isometric view of yet another humeral component; FIG. 7Bis a superior view of the humeral component of FIG. 7A; FIG. 7C is ananterior view of the humeral component of FIG. 7A; FIG. 7D is a lateralview of the humeral component of FIG. 7A; FIG. 7E is a cross sectionalview of the humeral component of FIG. 7A, taken along section line 7E-7Eof FIG. 7D; and FIG. 7F is a cross sectional view of the humeralcomponent of FIG. 7A, taken along section line 7F-7F of FIG. 7D;

FIG. 8A is an isometric view of yet another humeral component; FIG. 8Bis a lateral view of the humeral component of FIG. 8A; FIG. 8C is across sectional view of the humeral component of FIG. 8A, taken alongsection line 8C-8C of FIG. 8B; and FIG. 8D is a cross sectional view ofthe humeral component of FIG. 8A, taken along section line 8D-8D of FIG.8B;

FIG. 9A is an isometric view of a pin and a template; and FIG. 9B isanother isometric view of the template of FIG. 9A from a differentviewpoint;

FIG. 10A is an isometric view of the pin of FIG. 9A and a planar reamer;and FIG. 10B is another isometric view of a portion of the pin andplanar reamer of FIG. 10A from a different viewpoint;

FIG. 11A is an isometric view of a conical reamer; and FIG. 11B isanother isometric view of the conical reamer of FIG. 11A from adifferent viewpoint;

FIG. 12A is a top view of a cutting guide; FIG. 12B is a cross sectionalview of the cutting guide of FIG. 12A, taken along section line 12B-12Bof FIG. 12A; FIG. 12C is a front view of the cutting guide of FIG. 12A;FIG. 12D is a side view of the cutting guide of FIG. 12A; FIG. 12E is abottom view of the cutting guide of FIG. 12A; and FIGS. 12F, 12G, 12H,12I, and FIG. 12J are isometric views of the cutting guide of FIG. 12Afrom several different viewpoints;

FIG. 13A is an isometric view of another cutting guide with the pin ofFIG. 9A and two fasteners; and FIG. 13B is another isometric view of thecutting guide, pin, and fasteners of FIG. 13A from a differentviewpoint;

FIG. 14 is an isometric view of yet another cutting guide with twofasteners;

FIG. 15A is an isometric view of yet another cutting guide with the pinof FIG. 9A and four fasteners; and FIG. 15B is another isometric view ofthe cutting guide, pin, and fasteners of FIG. 15A from a differentviewpoint;

FIG. 16 is an isometric view of yet another cutting guide with twofasteners and a saw blade;

FIG. 17A is an isometric view of yet another cutting guide with threefasteners; FIG. 17B is another isometric view of the cutting guide andfasteners of FIG. 17A from a different viewpoint; and FIG. 17C isanother isometric view of the cutting guide and fasteners of FIG. 17Awith a drill, from the viewpoint of FIG. 17A;

FIG. 18 is an isometric view of yet another cutting guide with twofasteners;

FIG. 19A is an isometric view of yet another cutting guide; and FIG. 19Bis another isometric view of the cutting guide of FIG. 19A with threefasteners, from a different viewpoint;

FIG. 20A is an isometric view of an intact proximal humerus along thehumeral neck axis; and FIG. 20B is an isometric view of the proximalhumerus of FIG. 20A from a postero-medial viewpoint;

FIG. 21A is an isometric view of the proximal humerus of FIG. 20A alongthe humeral neck axis after a posterior bone resection has been made;and FIG. 21B is an isometric view of the proximal humerus of FIG. 21Afrom a postero-medial viewpoint;

FIG. 22A is an isometric view of the proximal humerus of FIG. 21A alongthe humeral neck axis after an inferior bone resection has been made;and FIG. 22B is an isometric view of the proximal humerus of FIG. 22Afrom a postero-medial viewpoint;

FIG. 23A is an isometric view of the proximal humerus of FIG. 22A alongthe humeral neck axis after an anterior bone resection has been made;and FIG. 23B is an isometric view of the proximal humerus of FIG. 23Afrom a postero-medial viewpoint;

FIG. 24A is an isometric view of the proximal humerus of FIG. 23A alongthe humeral neck axis after a superior bone resection has been made; andFIG. 24B is an isometric view of the proximal humerus of FIG. 24A from apostero-medial viewpoint;

FIG. 25A is an isometric view of the proximal humerus of FIG. 24A alongthe humeral neck axis after an inferior bone hole has been made; andFIG. 25B is an isometric view of the proximal humerus of FIG. 25A from apostero-medial viewpoint;

FIG. 26A is an isometric view of the proximal humerus of FIG. 25A alongthe humeral neck axis after anterior and posterior bone holes have beenmade; and FIG. 26B is an isometric view of the proximal humerus of FIG.26A from a postero-medial viewpoint;

FIG. 27 is an isometric view of the template and pin of FIG. 9Aoperatively arranged relative to a simplified humeral head representedby a hemisphere;

FIG. 28 is an isometric view of the template, pin, and simplifiedhumeral head of FIG. 27 operatively arranged relative to an alignmentguide;

FIG. 29 is an isometric view of the simplified humeral head of FIG. 27after a central pin hole has been made;

FIG. 30 is an isometric view of the planar reamer and pin of FIG. 10Aoperatively arranged relative to the simplified humeral head of FIG. 29;

FIG. 31 is an isometric view of the simplified humeral head of FIG. 30after a planar bone resection has been made perpendicular to the pinhole;

FIG. 32 is an isometric view of the cutting guide and fasteners of FIG.13A and a saw blade operatively arranged relative to the simplifiedhumeral head of FIG. 31;

FIG. 33 is an isometric view of the cutting guide and fasteners of FIG.15A and a saw blade operatively arranged relative to the simplifiedhumeral head of FIG. 31;

FIG. 34 is an isometric view of the cutting guide and fasteners of FIG.16 and a saw blade operatively arranged relative to the simplifiedhumeral head of FIG. 31;

FIG. 35 is an isometric view of the simplified humeral head of FIG. 32after anterior and posterior bone resections have been made;

FIG. 36 is an isometric view of the cutting guide and fasteners of FIG.17A and a saw blade operatively arranged relative to the simplifiedhumeral head of FIG. 35;

FIG. 37 is an isometric view of the cutting guide, fasteners, andsimplified humeral head of FIG. 36 operatively arranged relative to thedrill of FIG. 17C;

FIG. 38 is an isometric view of the simplified humeral head of FIG. 37after superior and inferior bone resections and superior, inferior,anterior, and posterior bone holes have been made;

FIG. 39 is an isometric view of the cutting guide and fasteners of FIG.19B operatively arranged with a proximal humerus;

FIG. 40 is an isometric view of the proximal humerus of FIG. 39, afterinferior, antero-superior, and postero-superior bone resections and boneholes have been made;

FIG. 41 is an isometric view of the conical reamer of FIG. 11Aoperatively arranged with the proximal humerus of FIG. 40;

FIG. 42 is an isometric view of the proximal humerus of FIG. 41, after aconical resection has been made; and

FIG. 43 is an isometric view of the proximal humerus of FIG. 42, afterthe humeral component of FIG. 7 has been implanted.

DETAILED DESCRIPTION

Standard medical planes of reference and descriptive terminology areemployed in this specification. A sagittal plane divides a body intoright and left portions. A mid-sagittal plane divides the body intobilaterally symmetric right and left halves. A coronal plane divides abody into anterior and posterior portions. A transverse plane divides abody into superior and inferior portions. Anterior means toward thefront of the body. Posterior means toward the back of the body. Superiormeans toward the head. Inferior means toward the feet. Medial meanstoward the midline of the body. Lateral means away from the midline ofthe body. Axial means toward a central axis of the body. Abaxial meansaway from a central axis of the body. Ipsilateral means on the same sideof the body. Contralateral means on the opposite side of the body. Thesedescriptive terms may be applied to an animate or inanimate body.

One of the objectives of the present technology is to provide aprosthesis for the articular surface of the proximal humerus that allowsfor a bone preserving and anatomically accurate surgical operation. Thedisclosed prosthesis requires several small bone cuts to remove a smallamount of bone from the upper humerus, but significantly less than astemmed prosthesis. However the small amount of bone removed may be justenough to allow improved access to a surgeon who also is placing aglenoid prosthesis, especially if the glenoid prosthesis uses an obliqueangle of insertion. The disclosed humeral prosthesis still rests on thesurface of the upper humerus and does not extend into the humeral shaft,unless the surgeon chooses to use a longer stemmed example.

The disclosed humeral prosthesis can be modified by varying the size,angle and relative location of each individual circle of a sphererelative to the other circles. The prosthesis may be altered in discreteregions to adapt the component precisely to cover or avoid certainsurrounding anatomical structures, such as the rotator cuff tendoninsertions of the teres minor, infraspinatus, supraspinatus, andsubscapularis muscles. This cannot be done with a prosthesis designed asa single hemisphere and having an articular margin which lies on aplane.

Another design, known as a stemless hemiarthroplasty prosthesis, alsouses a hemispherical humeral head implant placed on top of the upperhumerus after a standard humeral head cut has been made. Though thisdesign does not require the placement of a stem, the solid large metalhead is of the same volume and weight as a comparable head used in astemmed design, but is anchored by a shallow fixation apparatus.

An objective of the present technology is to disclose a prosthesis forthe articular surface of the proximal humerus having overlapping circlesof a sphere.

Another objective of the present technology is to disclose a prosthesisfor the articular surface of the proximal humerus having an ellipsoidshape of the humeral articular surface.

Still another objective of the present technology is to disclose aprosthesis for the articular surface of the proximal humerus having along stem example of a resurfacing type prosthesis.

Another objective of the present technology is to disclose a cuttingguide instrument used to prepare the bone to seat the humerusprosthesis.

Advantages of the present technology include the multiple joinedcircle-of-a-sphere design, which requires less removal of bone than astandard hemiarthroplasty. Due to significantly reduced volume, themetal humeral component weighs significantly less than a standardhemispherical humeral component of corresponding size, but providesnearly equal surface area coverage of the proximal humeral articularsurface. The reduced weight of the humeral component may improveshoulder kinematics. The reduced weight of the humeral component mayalso contribute to improved long-term stability by reducing looseningforces placed on the anchoring elements. Reduced volume of metal mayalso potentially reduce material costs of manufacturing the implant.

The humeral canal is not violated during the surgical proceduresdisclosed herein, reducing blood loss and marrow-fat emboli release intothe blood. The canal is also preserved for future stemmed arthroplastycomponents if revision surgery is ever required. This does not apply inthe case of the long stem example.

The undersurface design resulting from overlapping planar bone cutsprovides resistance to rotational forces and is potentially more stablethan a single flat cut. This may provide for improved long-termstability of the component. By making multiple oblique cuts through thehumeral head surface, a greater proportion of the component will beresting again the strong outer cortical bone of the humerus than astandard hemispherical prosthesis.

The present design does not require or reference the humeral canal todetermine proper location for bone cuts, thus the surgeon is free toposition the humeral component to best fit each patient's' individualanatomy. This is even more important in cases where deformity hasaltered the normal shape of the humerus.

The articular surface of the humeral prosthesis can be ellipsoid tobetter match the normal anatomy of the humerus. Current stemmed andresurfacing arthroplasty designs, due to the variable-offset feature ofstemmed designs and the bone preparation process of resurfacing designs,include only spherical humeral heads.

The most inferior circle of the prosthesis extends inferiorly to coverthe most medial aspect of the medial humeral neck bone, in order toreduce the incidence of impingement of the medial humerus against aglenoid prosthetic component. Retrieval studies of failed glenoidcomponents have shown that inferior impingement is a significantcontributor to glenoid loosening.

By placing the prosthesis more precisely in a location that betterreplicates the normal anatomy, motion across the glenohumeral joint maybe more smooth and stable, and eccentric forces placed upon the glenoidprosthesis may be reduced.

The current prosthesis can be finely adjusted by varying the size, angleand relative location of each individual circle of a sphere relative tothe other circles. This allows the prosthesis to be altered in discreteregions for clinical purposes.

Other objectives and advantages of this technology will become apparentfrom the following description taken in conjunction with theaccompanying drawings wherein are set forth, by way of illustration andexample, certain embodiments of the technology. The drawings containedherein constitute a part of this specification and include exemplaryembodiments of the present technology and illustrate various objects andfeatures thereof.

Referring to FIGS. 1A-1F, a humeral component 100 includes an articularsurface 102 and a bone-facing side 104 which is opposite to thearticular surface.

The humeral component 100 has a smooth, polished articular bearingsurface 102 which may articulate with a natural glenoid socket or aglenoid prosthetic component. The glenoid prosthetic component may be ofthe type disclosed in U.S. Provisional Patent Application No.61/776,398, filed Mar. 11, 2013, and entitled OBLIQUE-INSERTIONANCHORING MECHANISM FOR GLENOID PROSTHETIC COMPONENT; or the typedisclosed in U.S. patent application Ser. No. 14/042,258, filed Sep. 30,2013, and entitled GLENOID ARTHROPLASTY. The contents of these documentsare incorporated herein by reference. The glenoid component may bepolyethylene or another biocompatible material.

The prosthetic humeral component may be designed as multiple overlappingcircles of a sphere, where the sphere forms the articular surface 102. A“circle of a sphere” is a circle defined by the intersection of a sphereand a plane. If the plane contains the center of the sphere, then thecircle is called a “great circle”; otherwise, it is a “small circle.” A“spherical cap” is a three-dimensional portion of a sphere cut off by anintersecting plane. If the plane passes through the center of thesphere, the spherical cap is called a “hemisphere.” If the height of thespherical cap is less than the radius of the sphere, the spherical capis called a “minor spherical cap.” If the height of the spherical cap isgreater than the radius of the sphere, the spherical cap is called a“major spherical cap.” In this specification, any reference to a circleof a sphere is also a reference to the corresponding spherical cap, andany reference to a spherical cap is also a reference to thecorresponding circle of the sphere.

Together these overlapping circles of a sphere, and correspondingspherical caps, form an articular surface which is nearly hemispherical,or partly spherical, but with significantly less volume of material thana solid hemisphere due to the multiple planar surfaces on the bonefacing side 104, which in a solid hemisphere would be flat. Thearticular surface area created by the overlapping circles of a spherenearly covers the native articular surface of the proximal humerus.Referring to FIG. 1A, each one of the planar surfaces corresponds to oneof the overlapping circles of a sphere or spherical caps. All of thespherical surfaces are co-radial; they share the same spherical centerand all spherical radii are equal, so that the articular surface 102 isan uninterrupted spherical surface. Some examples of the presenttechnology utilize four overlapping circles of a sphere, but otherexamples may have three, five or more overlapping circles of a sphere.

In an alternate version of the technology, the prosthetic humeralcomponent 100 may have an ellipsoid or ovoid articular surface 102,rather than a spherical articular surface. The circles of an ellipsoidor ovoid, and the corresponding caps, may be overlapped to create thesame effect of covering a similar amount of surface area with a reducedvolume of material. The ellipsoid or ovoid articular surface has a firstradius (or first diameter) in a first plane or along a first axis whichis dimensionally different from a second radius (or second diameter) ina second plane or along a second axis. The first radius may be larger orsmaller than the second radius. Referring to FIGS. 1C, 1E, and 1F, theradius of articular surface 102 in FIG. 1C may be dimensionallydifferent from the radius of articular surface 102 in FIG. 1F when thearticular surface 102 is ellipsoid or ovoid instead of spherical. Forexample, an ellipsoid or ovoid articular surface may have a largerdiameter along the superior-inferior axis in the coronal plane than inthe transverse plane, or vice versa. The increased radius of curvatureof an ellipsoid or ovoid bearing surface in a given direction may reducethe constraint of the humeral head within the glenohumeral joint in thatdirection. This reduced constraint may result in reduced eccentricforces applied to the bearing surface and reduced risk of implantloosening. The increased radius of curvature may be oriented relative tothe prevailing direction of articulation of a given joint, or relativeto an articulation direction in which impingement, loosening, or otherstress-related effects are known to occur. These ellipsoid or ovoidshapes may also be narrower at the superior end and broader at theinferior end. The ellipsoid or ovoid shape may better replicate thenormal articular surface of the humeral head, better replicating thekinematics of the shoulder during articulation, and better matching themorphology of the natural articulating surface, allowing for better fitand transition between the implant and the bone, at least in somepatients.

Humeral components according to the present technology may also bedesigned as a hemisphere, spherical cap, ellipsoid cap, or ovoid capwith a tapered polygonal socket forming the bone-facing side. Thetapered polygonal socket may be designed by extruding a polygonal shapefrom the flat side of the hemisphere or cap toward the articular surfacewhile tapering the sides of the polygonal shape inward. The polygonalshape may be a triangle, square, rectangle, pentagon, or other polygonalshape, and may be regular or irregular, and may be symmetrically orasymmetrically disposed relative to the center of the hemisphere or cap.The sides of the polygonal shape may all have the same taper angle,although one or more sides may have a different taper angle. It can beappreciated that the bone-facing side 104 of humeral component 100 maybe designed as a tapered rectangular socket, and similarly for humeralcomponents 200, 300, 400, 500, 600 discussed below.

Humeral component 100 may include four planar surfaces 120, 122, 124,126 in a concave arrangement in which the planar surfaces convergetogether as they approach the middle of the articular surface 102, asseen best in FIG. 1A. Other examples may include three, five, or moreplanar surfaces in a concave arrangement. More specifically, one examplemay include planar surfaces 120, 122, 124. The planar surfaces divergeas they extend away from the middle of the articular surface 102, andintersect the articular surface to establish an articular margin 106around a perimeter of the humeral component 100. The articular marginmay be described as scalloped or having one or more indentations 129.Each one of the planar surfaces intersects each other planar surface atan obtuse angle, although right angles and acute angles are alsocontemplated. Planar surfaces 120, 124 intersect along a line 119,planar surfaces 120, 126 intersect along a line 121, planar surfaces120, 122 intersect along a line 123, planar surfaces 124, 126 intersectalong a line 125, and planar surfaces 124, 122 intersect along a line127. The lines 119, 121, 123, 125, 127 may also be referred to asintersections, edges, or internal corners, and may include fillet radii,as best seen in FIG. 1E. Referring to FIG. 1E, lines 119, 123, 127intersect at a first point 111; and lines 119, 121, 125 intersect at asecond point 113. Lines 123, 121 and 127, 125 also intersect whenextended. Line 119 in this example may extend in a superior-inferiordirection when the humeral component 100 is implanted.

The humeral component 100 may have a roughened or porous bone-facingside 104, or undersurface, which rests on the prepared bone of thehumerus when the humeral component is implanted. These roughened orporous surfaces assist in bony apposition between the implant and theunderlying subcondylar bone encouraging bony ingrowth into the porosityof the bone-facing side once the humeral component is implanted. Fromthis undersurface or bone-facing side 104, at least one anchoringelement 128 projects outwardly; the example shown includes threeanchoring elements 128, 130, 132. The anchoring elements project intothe humeral bone when the humeral component is implanted, and may anchorthe humeral component to prevent loosening or micromotion. The anchoringelements may be pegs which are round, cruciate, or have fins, or haveanother cross sectional shape for bone fixation. The anchoring elementsmay include fenestrations. Some of the examples disclosed herein utilizethree pegs, but the number of pegs may vary. The pegs may be parallel,converging, diverging, or skew. The pegs may be smooth, matte, rough, orporous to promote bone cement fixation or bone ingrowth. The illustratedanchoring elements 128, 130, 132 are cylindrical and parallel to oneanother. Anchoring element 128 is longer than anchoring elements 130,132, and may therefore be suited for implantation in an inferior aspectof the humeral head/neck.

Humeral component 100 is bilaterally symmetric about a plane throughline 119, and may therefore be implanted in right or left shoulders.Humeral component 100 may be implanted so that planar surface 126 coversa superior aspect of the humeral head, planar surface 122 covers aninferior aspect of the humeral head, planar surfaces 120 and 124 coveranterior and posterior portions of the humeral head, anchoring element128 extends through the inferior aspect of the humeral head andoptionally into the humeral neck, and anchoring elements 130, 132 extendinto anterior and posterior portions of the humeral head. The outerportion, or rim, of planar surface 126 faces at least a portion of therotator cuff, and, because planar surface 126 is indented to form theindentation 129 along the articular margin 106, a space exists betweenthe rim of planar surface 126 and the rotator cuff. This space providesrelief, or room, for the rotator cuff to function without excessiverubbing against the outer portion, or rim, of the humeral component 100,thus reducing the risk of rotator cuff damage.

In one example, the inferior-most peg may be curved and elongated,forming a stem which extends distally into the diaphysis of the humerus,following the curve of the medial neck of the humerus. This inferior pegor stem may be manufactured as one piece with the bearing surfacecomponent, or the peg or stem may be modular, supplied in varyingthickness and lengths. A modular peg may be attached to the bearingportion of the component via a Morse taper, screw-in or other connectionmechanism.

In another embodiment, the location of the pegs on the backside of theprosthetic component may project in a more vertical direction. Thisembodiment may be suitable for a surgeon utilizing asubscapularis-preserving surgical technique where the only exposure tothe humerus is from the superior direction.

The prosthesis may be fixed in place with bone cement, or it may have aroughened surface or porous coating on the undersurface for cementless(press-fit) use.

The entire humeral component 100 may be made of a solid metal piece. Inother examples, the prosthesis may be made of another material, such asany of the materials commonly used in orthopaedic joint arthroplasty,such as ceramic, composite, polyethylene or pyrocarbon. Combinations ofmaterials may also be used.

Referring to FIGS. 2A-2F, another humeral component 200 includes anarticular surface 202 and a bone-facing side 204 which is opposite tothe articular surface. Humeral component 200 includes the followingfeatures, which may be substantially similar to, or the same as, thecorresponding features of humeral component 100: planar surfaces 220,222, 224, 226; lines 219, 221, 223, 225, 227; points 211, 213; andanchoring elements 228, 230, 232. In an alternate version of thetechnology, the prosthetic humeral component 200 may have an ellipsoidor ovoid articular surface 202, rather than a spherical articularsurface. The planar surfaces 220, 222, 224, 226 are in a concavearrangement in which the planar surfaces converge together as theyapproach the middle of the articular surface 202, as seen best in FIG.2A. Each one of the planar surfaces intersects each other planar surfaceat an obtuse angle, although right angles and acute angles are alsocontemplated. Fillet radii are present along lines 221, 225 and absentalong lines 219, 223, 227. The illustrated anchoring elements 228, 230,232 are cylindrical and parallel to one another. These anchoringelements include bilateral longitudinal grooves 236. Anchoring element228 is longer than anchoring elements 230, 232, and may therefore besuited for implantation in an inferior aspect of the humeral head/neck.

Humeral component 200 is bilaterally symmetric about a plane throughline 219, and may therefore be implanted in right or left shoulders.Humeral component 200 may be implanted so that planar surface 226 coversa superior aspect of the humeral head, planar surface 222 covers aninferior aspect of the humeral head, planar surfaces 220 and 224 coveranterior and posterior portions of the humeral head, anchoring element228 extends through the inferior aspect of the humeral head andoptionally into the humeral neck, and anchoring elements 230, 232 extendinto anterior and posterior portions of the humeral head.

Referring to FIGS. 3A-3F, yet another humeral component 300 includes anarticular surface 302 and a bone-facing side 304 which is opposite tothe articular surface. Humeral component 300 includes the followingfeatures, which may be substantially similar to, or the same as, thecorresponding features of humeral component 100: planar surfaces 320,322, 324, 326; lines 319, 321, 323, 325, 327; fillet radii; points 311,313; and anchoring elements 328, 330, 332. In an alternate version ofthe technology, the prosthetic humeral component 300 may have anellipsoid or ovoid articular surface 302, rather than a sphericalarticular surface. The planar surfaces 320, 322, 324, 326 are in aconcave arrangement in which the planar surfaces converge together asthey approach the middle of the articular surface 302, as seen best inFIG. 3A. Each one of the planar surfaces intersects each other planarsurface at an obtuse angle, although right angles and acute angles arealso contemplated. The illustrated anchoring elements 330, 332 arecylindrical and parallel to one another. Anchoring element 328 is curvedoutwardly, and is longer than anchoring elements 330, 332, and maytherefore be suited for implantation in an inferior aspect of thehumeral head/neck. Anchoring element 328 also includes four longitudinalgrooves 336, which are evenly arranged around anchoring element 328.Anchoring element 328 may be described as having a diamond-shaped orstar-shaped cross section.

Humeral component 300 is bilaterally symmetric about a plane throughline 319, and may therefore be implanted in right or left shoulders.Humeral component 300 may be implanted so that planar surface 326 coversa superior aspect of the humeral head, planar surface 322 covers aninferior aspect of the humeral head, planar surfaces 320 and 324 coveranterior and posterior portions of the humeral head, anchoring element328 extends through the inferior aspect of the humeral head andoptionally into the humeral neck, and anchoring elements 330, 332 extendinto anterior and posterior portions of the humeral head.

Referring to FIGS. 4A-4B, yet another humeral component 400 includes anarticular surface 402 and a bone-facing side 404 which is opposite tothe articular surface. Humeral component 400 includes the followingfeatures, which may be substantially similar to, or the same as, thecorresponding features of humeral component 100: planar surfaces 420,422, 424, 426; lines 419, 421, 423, 425, 427; fillet radii; points 411,413; and anchoring elements 428, 430, 432. In an alternate version ofthe technology, the prosthetic humeral component 400 may have anellipsoid or ovoid articular surface 402, rather than a sphericalarticular surface. The planar surfaces 420, 422, 424, 426 are in aconcave arrangement in which the planar surfaces converge together asthey approach the middle of the articular surface 402, as seen best inFIG. 4A. The planar surfaces diverge as they extend away from the middleof the articular surface 402, and intersect the articular surface toestablish an articular margin 406 around a perimeter of the humeralcomponent 400. The articular margin may be described as scalloped orhaving one or more indentations 429. Each one of the planar surfacesintersects each other planar surface at an obtuse angle, although rightangles and acute angles are also contemplated. Planar surface 426 has asmaller area than planar surface 422, and may be described as beingindented, or centrally offset, particularly in comparison to planarsurface 422. Humeral component 400 includes a fourth anchoring element434. The illustrated anchoring elements 428, 430, 432, 434 arecylindrical and parallel to one another. Anchoring elements 428, 430,432, 434 also include bilateral longitudinal grooves 436.

Humeral component 400 is bilaterally symmetric about a plane throughline 419, and may therefore be implanted in right or left shoulders.Humeral component 400 may be implanted so that planar surface 426 coversa superior aspect of the humeral head, planar surface 422 covers aninferior aspect of the humeral head, planar surfaces 420 and 424 coveranterior and posterior portions of the humeral head, anchoring element428 extends through the inferior aspect of the humeral head andoptionally into the humeral neck, anchoring elements 430, 432 extendinto anterior and posterior portions of the humeral head, and anchoringelement 434 extends into the superior aspect of the humeral head. Theouter portion, or rim, of planar surface 426 faces at least a portion ofthe rotator cuff, and, because planar surface 426 is indented to formthe indentation 429 along the articular margin 406, a space existsbetween the rim of planar surface 426 and the rotator cuff. This spaceprovides relief, or room, for the rotator cuff to function withoutexcessively rubbing against the outer portion, or rim, of the humeralcomponent 600, thus reducing the risk of rotator cuff damage.

Referring to FIGS. 5A-5B, yet another humeral component 500 includes anarticular surface 502 and a bone-facing side 504 which is opposite tothe articular surface. Humeral component 500 includes the followingfeatures, which may be substantially similar to, or the same as, thecorresponding features of humeral component 100: planar surfaces 520,522, 524, 526; lines 519, 521, 523, 525, 527; fillet radii; points 511,513; and anchoring elements 528, 530, 532. In an alternate version ofthe technology, the prosthetic humeral component 500 may have anellipsoid or ovoid articular surface 502, rather than a sphericalarticular surface. The planar surfaces 520, 522, 524, 526 are in aconcave arrangement in which the planar surfaces converge together asthey approach the middle of the articular surface 502, as seen best inFIG. 5A. The planar surfaces diverge as they extend away from the middleof the articular surface 502, and intersect the articular surface toestablish an articular margin 506 around a perimeter of the humeralcomponent 500. The articular margin may be described as scalloped orhaving one or more indentations 529. Each one of the planar surfacesintersects each other planar surface at an obtuse angle, although rightangles and acute angles are also contemplated. Planar surface 526 has asmaller area than planar surface 522, and may be described as beingindented, or centrally offset, particularly in comparison to planarsurface 522. Humeral component 500 includes a fourth anchoring element534. The illustrated anchoring elements 528, 530, 532, 534 arecylindrical and parallel to one another. Anchoring element 528 may belonger than anchoring elements 530, 532, 534. Anchoring elements 528,530, 532, 534 also include bilateral longitudinal grooves 536.

Humeral component 500 is bilaterally symmetric about a plane throughline 519, and may therefore be implanted in right or left shoulders.Humeral component 500 may be implanted so that planar surface 526 coversa superior aspect of the humeral head, planar surface 522 covers aninferior aspect of the humeral head, planar surfaces 520 and 524 coveranterior and posterior portions of the humeral head, anchoring element528 extends through the inferior aspect of the humeral head andoptionally into the humeral neck, anchoring elements 530, 532 extendinto anterior and posterior portions of the humeral head, and anchoringelement 534 extends into the superior aspect of the humeral head. Theouter portion, or rim, of planar surface 526 faces at least a portion ofthe rotator cuff, and, because planar surface 526 is indented to formthe indentation 529 along the articular margin 506, a space existsbetween the rim of planar surface 526 and the rotator cuff. This spaceprovides relief, or room, for the rotator cuff to function, thusreducing the risk of rotator cuff damage.

Referring to FIGS. 6A-6Q, yet another humeral component 600 includes anarticular surface 602 and a bone-facing side 604 which is opposite tothe articular surface. Humeral component 600 includes the followingfeatures, which may be substantially similar to, or the same as, thecorresponding features of humeral component 100: planar surfaces 620,622, 624, 626; lines 619, 621, 623, 625, 627; fillet radii; points 611,613; and anchoring elements 628, 630, 632. In an alternate version ofthe technology, the prosthetic humeral component 600 may have anellipsoid or ovoid articular surface 602, rather than a sphericalarticular surface. The planar surfaces 620, 622, 624, 626 are in aconcave arrangement in which the planar surfaces converge together asthey approach the middle of the articular surface 602, as seen best inFIG. 6A. The planar surfaces diverge as they extend away from the middleof the articular surface 602, and intersect the articular surface toestablish an articular margin 606 around a perimeter of the humeralcomponent 600. The articular margin may be described as scalloped orhaving one or more indentations 629. Each one of the planar surfacesintersects each other planar surface at an obtuse angle, although rightangles and acute angles are also contemplated. Planar surface 626 has asmaller area than planar surface 622, and may be described as beingindented, or centrally offset, particularly in comparison to planarsurface 622. Humeral component 600 includes a fourth anchoring element634 and a conical surface 674. The illustrated anchoring elements 628,630, 632, 634 are cylindrical and parallel to one another. Anchoringelement 628 may be longer a than anchoring elements 630, 632, 634.Anchoring element 634 may be shorter than anchoring elements 628, 630,632. Anchoring elements 628, 630, 632, 634 also include bilaterallongitudinal grooves 636. The conical surface 674 is present around anoutermost portion of the bone-facing side 604, and is best seen in FIG.6D in the vicinity of the outermost portions of lines 621, 623, 625,627.

Humeral component 600 is bilaterally symmetric about a plane throughline 619, and may therefore be implanted in right or left shoulders.Humeral component 600 may be implanted so that planar surface 626 coversa superior aspect of the humeral head, planar surface 622 covers aninferior aspect of the humeral head, planar surfaces 620 and 624 coveranterior and posterior portions of the humeral head, anchoring element628 extends through the inferior aspect of the humeral head andoptionally into the humeral neck, anchoring elements 630, 632 extendinto anterior and posterior portions of the humeral head, and anchoringelement 634 extends into the superior aspect of the humeral head. Theouter portion, or rim, of planar surface 626 faces at least a portion ofthe rotator cuff, and, because planar surface 626 is indented to formthe indentation 629 along the articular margin 606, a space existsbetween the rim of planar surface 626 and the rotator cuff. This spaceprovides relief, or room, for the rotator cuff to function, thusreducing the risk of rotator cuff damage.

FIGS. 6F and 6G illustrate humeral component 600 in cross sectionalviews. In each view, two additional smaller size humeral components600′, 600″ are superimposed on humeral component 600 to show certainaspects of the design rationale governing the progression from one sizeto the next. The illustrated design rationale may apply to any of thehumeral components disclosed herein. If humeral component 600 isreferred to as a large size, then humeral component 600′ is a mediumsize, and humeral component 600″ is a small size. However, these small,medium, and large size designations are for the purposes of illustrationonly. It is understood that a full size range of humeral components mayinclude more than three sizes, including sizes larger than humeralcomponent 600, sizes smaller than humeral component 600″, and/or sizesin between those illustrated herein.

The superimposed cross sections of humeral components 600, 600′, 600″reveal that the planar surfaces 620, 622, 624, 626; lines 619, 621, 623,625, 627; fillet radii; points 611, 613; anchoring elements 628, 630,632, 634, and conical surface 674 are all identical among the threedifferent sizes. In other words, the same bone preparation—saw cuts,drilled holes, and conical ream—may be performed for all humeralcomponent sizes, and any size humeral component may be implanted onto aparticular prepared humerus.

The superimposed cross sections of humeral components 600, 600′, 600″also show that the various articular surfaces 602, 602′, 602″ areneither concentric nor tangent. Instead, each articular surface 602,602′, 602″ passes through a defined circle 603, which appears as a pairof points 603 in each FIGS. 6F and 6G. This defined circle 603 may bethought of as a gage circle which has a fixed relationship to thefeatures of the bone-facing side 604. The defined circle may lie in thesame plane as line 619, for example, or planar surfaces 744, 844described below. The articular surface 602″ of the small humeralcomponent 600″ protrudes farther above the circle 603 than do thearticular surfaces 602′, 602 of the medium and large humeral components600′, 600. Later in this specification, it will be shown that thisdefined circle 603 may correspond to a depth stop feature on a planarreamer.

Referring to FIGS. 7A-7F, yet another humeral component 700 includes anarticular surface 702 and a bone-facing side 704 which is opposite tothe articular surface. The articular surface is smooth and polished, andmay be spherical, elliptical, or ovoid. Humeral component 700 may bedesigned with four overlapping circles of a sphere, or as a hemispherewith a tapered, triangular, flat-bottom socket forming the bone-facingside.

Humeral component 700 may include four planar surfaces 744, 762, 764,766 in a concave arrangement in which the planar surfaces 762, 764, 766converge together as they approach the middle of the articular surface702 and the planar surface 744, as seen best in FIG. 7A. Other examplesmay include three, five, or more planar surfaces in a concavearrangement. Each one of the planar surfaces intersects each otherplanar surface at an obtuse angle, although right angles and acuteangles are also contemplated. Planar surfaces 744, 762 intersect along aline 757, planar surfaces 744, 764 intersect along a line 759, andplanar surfaces 744, 766 intersect along a line 761. Planar surfaces762, 764; 764, 766; and 766, 762 also intersect when extended. The lines757, 759, 761 may also be referred to as intersections, edges, orinternal corners, and may include fillet radii, as best seen in FIG. 7D.Referring to FIG. 7D, lines 757, 759 intersect at a first point 711;lines 759, 761 intersect at a second point 713; and lines 757, 761intersect at a third point 715. Humeral component 700 also includes aconical surface 774, which is present in the vicinity of the outermostportions of lines 757, 759, 761, as best seen in FIG. 7D.

The humeral component 700 may have a roughened bone-facing side 704, orundersurface, which rests on the prepared bone of the humerus when thehumeral component is implanted. From this undersurface or bone-facingside 704, at least one anchoring element 768 projects outwardly. Theexample shown includes three anchoring elements 768, 770, 772 protrudingfrom planar surfaces 762, 764, 766, respectively. The anchoring elementsproject into the humeral bone when the humeral component is implanted,and may anchor the humeral component to prevent loosening ormicromotion. The anchoring elements may be pegs which are round,cruciate, or have fins, or have another cross sectional shape for bonefixation. The anchoring elements may include fenestrations. Some of theexamples disclosed herein utilize three pegs, but the number of pegs mayvary. The pegs may be parallel, converging, diverging, or skew. The pegsmay be smooth, matte, rough, or porous to promote bone cement fixationor bone ingrowth. The illustrated anchoring elements 768, 770, 772 arecylindrical and parallel to one another.

Humeral component 700 is bilaterally symmetric about a plane throughsection line 7F-7F of FIG. 7D, and trilaterally symmetric about an axisnormal to planar surface 744. Humeral component 700 may therefore beimplanted in right or left shoulders. Humeral component 700 may beimplanted so that planar surface 764 covers an inferior aspect of thehumeral head, planar surfaces 762 and 766 cover anterior-superior andposterior-superior portions of the humeral head, anchoring element 770extends through the inferior aspect of the humeral head and optionallyinto the humeral neck, and anchoring elements 768, 772 extend intoanterior and posterior portions of the humeral head. However, due to itstrilateral symmetry, humeral component 700 may also be implanted so thatplanar surface 762 or planar surface 766 covers the inferior aspect ofthe humeral head instead of planar surface 764.

Referring to FIGS. 8A-8D, yet another humeral component 800 includes anarticular surface 802 and a bone-facing side 804 which is opposite tothe articular surface.

Humeral component 800 includes the following features, which may besubstantially similar to, or the same as, the corresponding features ofhumeral component 700: planar surfaces 844, 862, 864, 866; lines 857,859, 861; points 811, 813, 815; conical surface 874; anchoring elements868, 870, 872. In an alternate version of the technology, the prosthetichumeral component 800 may have an ellipsoid or ovoid articular surface802, rather than a spherical articular surface. The planar surfaces 844,862, 864, 866 are in a concave arrangement in which the planar surfaces862, 864, 866 converge together as they approach the middle of thearticular surface 802 and the planar surface 844, as seen best in FIG.8A. Each one of the planar surfaces intersects each other planar surfaceat an obtuse angle, although right angles and acute angles are alsocontemplated. Planar surfaces 862, 864 intersect along a line 863,planar surfaces 864, 866 intersect along a line 865, and planar surfaces862, 866 intersect along a line 867. No fillet radii are shown in thisexample. The illustrated anchoring elements 868, 870, 872 arecylindrical and parallel to one another. Anchoring element 870 alsoincludes four longitudinal grooves 876 which are equally spaced aroundthe anchoring element. Anchoring element 870 may be described as havinga cruciate or plus-shaped cross section. Humeral component 800 includesa planar surface 878, which is present in the vicinity of the outermostportions of planar surfaces 862, 864, 866, as best seen in FIG. 8A.Planar surface 878 may be parallel to planar surface 844.

Humeral component 800 is bilaterally symmetric about a plane throughsection line 8C-8C of FIG. 8B, and trilaterally symmetric about an axisnormal to planar surface 844. Humeral component 800 may therefore beimplanted in right or left shoulders. Humeral component 800 may beimplanted so that planar surface 864 covers an inferior aspect of thehumeral head, planar surfaces 862 and 866 cover anterior-superior andposterior-superior portions of the humeral head, anchoring element 870extends through the inferior aspect of the humeral head and optionallyinto the humeral neck, and anchoring elements 868, 872 extend intoanterior and posterior portions of the humeral head. However, due to itstrilateral symmetry, humeral component 800 may also be implanted so thateither planar surface 862 or 866 covers the inferior aspect of thehumeral head instead of planar surface 864.

Referring to FIG. 9A, a guide wire or pin 900 and a template 1000 areshown in an operative arrangement. The template 1000 may be used toestablish the desired orientation of the implanted humeral componentrelative to the intact proximal humeral anatomy, and may guide insertionof the pin 900 into the humeral head. The desired orientation of thehumeral component may relate to an axis which is normal to a centralportion of the intact articular surface of the humeral head, or parallelto the intact humeral neck axis.

The pin 900 is a slender elongated shaft 902 which extends between aproximal end 904 and a distal tip 906. The shaft 902 may be circular incross-section as shown, or non-circular in cross-section. The proximalend 904 may include a torque connector for connection to a T-handle,drill, or other torque source. The distal tip 906 may be threaded,fluted for cutting, pointed, faceted as in a trocar tip, rounded, orblunt.

Referring to FIGS. 9A-9B, the template 1000 includes a shaft 1002 whichextends between a proximal end 1004 and a distal working portion 1006.The proximal end 1004 may include a handle or a coupling. The workingportion 1006 includes a round perimeter rim 1008 which may be connectedto the shaft 1002 by one or more arms 1010. The example shown includesbilateral straight arms 1010, 1012 interposed between bilateralbifurcated arms 1014, 1016. One or more apertures 1018 may extendbetween the arms; six apertures 1018 are shown in the example. Theworking portion 1006 has a bone-facing side 1020 and an opposite side1022. The bone-facing side may be concave as shown, convex, or flat. Theopposite side 1022 may complement the bone-facing side 1020. One or moreprojections 1024 may extend from the rim 1008; three projections 1024,1026, 1028 are shown, equally spaced around the rim 1008. The shaft 1002may include a central cannulation 1030 which receives the pin 900.

Referring to FIG. 28, an alignment guide 1100 is shown in use with thepin 900 and the template 1000 relative to a simplified humeral head 40.The alignment guide 1100 may provide additional anatomical referencingbeyond that provided by the template 1000, in order to set the desiredorientation of the implanted humeral component relative to the intactproximal humeral and forearm anatomy.

The alignment guide 1100 includes a shaft 1102 which extends between aproximal handle 1104 and a distal working portion 1106. In use, theshaft 1102 is aligned with the patient's forearm in consideration ofaligning the pin 900 in the desired rotational anteversion andretroversion of the patient. The working portion 1106 includes a plate1108 and at least one socket 1110 for releasably or permanently couplingto the shaft 1102. The plate 1108 may include a humeral shaft extension1112, an articular bar 1114, and a post 1116. The articular bar 1114 maycross the humeral shaft extension 1112 at an oblique angle to form a “T”shape. The post 1116 may extend perpendicular to the articular bar 1114opposite the humeral shaft extension 1112. The socket 1110 may belocated in the area where the articular bar 1114 crosses the humeralshaft extension 1112. The working portion 1106 may include a secondsocket (not visible in FIG. 28) on an opposite side of the plate 1108from the socket 1110. The shaft 1102 may be releasably coupled to eithersocket to provide configurations suitable for right or left shoulderprocedures.

Referring to FIGS. 10A-10B, the pin 900 and a planar reamer 1400 areshown in an operative arrangement. The planar reamer 1400 may be used tocut a planar bone resection 44 which is perpendicular to the axis of thepin 900 and which may have an outer diameter corresponding to thedefined circle 603. The bone resection 44 may correspond to planarsurfaces 744, 844, or it may correspond to lines 119, 219, 319, 419,519, 619.

The planar reamer 1400 includes a shaft 1402 which extends between aproximal end 1404 and a distal working portion 1406. The proximal end1404 may include a handle or a coupling; a torque coupling 1405 is shownfor coupling the planar reamer 1400 to a T-handle, drill, or othertorque driver. The working portion 1406 includes a round perimeter rim1408 which may be connected to the shaft 1402 by one or more arms 1410.The example shown includes bilateral arms 1410, 1412. One or moreapertures 1418 may extend between the arms; two apertures are shown inthe example. The working portion 1406 has a bone-facing side 1420 and anopposite side 1422. The bone-facing side 1420 is flat. Cutting features1424 are present on the bone-facing side 1420. In this example, thecutting features 1424 include a series of alternating teeth 1426 andgrooves 1428 with concentric circular patterns of crossing grooves 1429,which may be referred to as chip breakers. Relief channels 1432 may beincluded around the outer portion of each arm 1410, 1412 to provideclearance for the tools used to fabricate the cutting features 1424and/or to delimit an outer diameter of the cutting features. Acontinuous smooth planar surface 1434 extends completely around theperimeter rim 1408 on the bone-facing side 1420, forming a boundarywithin which all of the cutting features 1424 are contained. The surface1434 may be coplanar with the cutting features 1424, for example thepeaks of the teeth 1426 or the valleys of the grooves 1428.Alternatively, the surface 1434 may lie above or below the cuttingfeatures. The surface 1434 functions as a depth stop in use, as will bedescribed later. An inner edge 1436 of the surface 1434, excluding anyinterruption caused by the relief channels 1432, may correspond to thedefined circle 603 described above. The opposite side 1422 maycomplement the bone-facing side 1420. The shaft 1402 may include acentral cannulation 1430 which receives the pin 900.

Another example of a planar reamer has a plurality of arms that extendradially from the shaft to the rim like spokes on a wheel. This examplemay or may not have the continuous smooth planar surface that extendscompletely around the perimeter rim on the bone-facing side. Thisexample may have one or more radially extending cutting teeth per arm.Because this example has through openings between the cutting teeth, thebone and articular cartilage fragments are more easily cleared and thereamer is less likely to clog while reaming.

Referring to FIGS. 11A-11B, a conical reamer 1500 includes a shaft 1502which extends between a proximal end 1504 and a distal working portion1506. The conical reamer 1500 may be used to cut a conical boneresection 74 which corresponds to conical surface 674, 774, 874. Theproximal end 1504 may include a handle or a coupling; a blunt proximalend is shown. The working portion 1506 includes a round perimeter rim1508 which may be connected to the shaft 1502 by one or more arms 1510.The example shown includes a plurality of radially extending arms 1510.One or more apertures 1518 may extend between the arms; a plurality ofapertures is shown in the example. However, a roughened file-liketissue-cutting surface may also extend the working portion 1506 allowingrasp-like tissue removal. The working portion 1506 has a bone-facingside 1520 and an opposite side 1522. The bone-facing side includes aconical surface 1512 surrounding a central planar surface 1514 which isperpendicular to the shaft 1502. Cutting features 1524 are present onthe bone-facing side. In this example, the cutting features 1524 includea series of radial teeth 1526 on the leading side of each arm 1510(depending on the direction of rotation, clockwise or counterclockwise).A relief channel 1532 may be included between the central planar surface1514 and the conical surface 1512. The planar surface 1514 functions asa depth stop in use, as will be described later. The opposite side 1522may complement the bone-facing side 1520. The shaft 1502 may include acentral cannulation 1530 which receives the pin 900.

Specific preparations of the proximal humeral bone surface are disclosedin order to accommodate the multi-planar undersurfaces of the prostheticcomponents so the undersurfaces rests flush against the bone. Theproximal humeral bone may be prepared with the use of a cutting guidewhich rests on the head of the humerus. The cutting guide has slotswhich guide a cutting tool such as an oscillating saw blade to make bonecuts corresponding to the particular design of the undersurface of thehumeral prosthesis. The humeral cutting guide may be designed to be usedby a surgeon utilizing a standard subscapularis tenotomy or lessertuberosity osteotomy, but may also be adapted to a surgeon utilizing asubscapularis-preserving technique. Various cutting guides will now bedescribed.

Referring to FIGS. 12A-12J, a cutting guide 1600 may be referred to as acut and drill guide or as an all in one guide. The cutting guide 1600may be used to guide a cutting tool, such as a saw blade, to cut fourplanar bone resections 20, 22, 24, 26 corresponding to planar surfaces120, 122, 124, 126 of humeral component 100, or the planar surfaces ofhumeral components 200, 300, 400, 500, 600. The cutting guide 1600 mayalso be used to guide a cutting tool, such as a drill or reamer, to cutbone holes 28, 30, 32 corresponding to anchoring elements 128, 130, 132of humeral component 100, or the anchoring elements of humeralcomponents 200, 300, 400, B 500, 600. The cutting guide 1600 may alsoserve the function of the template 1000.

The cutting guide 1600 includes a cylindrical body 1608 terminating atone end in a spherical shell or cup 1610. The cutting guide 1600 has abone-facing side 1609 which includes the perimeter rim and concaveinterior of the spherical cup 1610. Three holes 1628, 1630, 1632 extendlengthwise through the cutting guide 1600, corresponding to the relativearrangement of anchoring elements 128, 130, 132 of humeral component100, or the anchoring elements of humeral components 200, 300, 400, 500,600. A fourth hole (not shown) may be included in the cutting guide1600, corresponding to anchoring elements 434, 534, 634 of humeralcomponents 400, 500, 600. One or more apertures 1612 may also extendlengthwise through the cutting guide 1600 to provide visualizationwindows and/or to reduce weight. Three apertures 1612, 1613, 1614 areshown in the example, interposed between the holes 1628, 1630, 1632.Four slots 1620, 1622, 1624, 1626 extend obliquely through the cuttingguide 1600, corresponding to the relative arrangement of planar surfaces120, 122, 124, 126 of humeral component 100, or the planar surfaces ofhumeral components 200, 300, 400, 500, 600. It will be appreciated thatthe number and arrangement of holes and/or slots in the illustratedcutting guide 1600 may be modified to correspond to the number andarrangement of anchoring elements and/or planar surfaces of humeralcomponents 700, 800. One or more holes 1616 may extend through thecutting guide 1600 near the rim of the spherical cup 1610 to receivepins to fix the cutting guide 1600 to the humeral head prior to makingany bone resections or holes; ten holes 1616, 1646, 1647, 1648, 1649,1650, 1651, 1652, 1653, 1654 are shown. Holes 1646, 1647, 1648, 1651,1652, 1653 are all parallel, and holes 1646, 1653; 1647, 1652; and 1648,1651 are coaxial. Referring to FIG. 12E, one or more projections 1656may extend from the interior of the spherical cup 1610 to engage thearticular surface of the humeral head. The example shows threeprojections 1656, 1657, 1658.

Referring to FIGS. 13A-13B, a cutting guide 1800, the pin 900, and twofasteners 1890, 1892 are shown in an operative arrangement. The cuttingguide 1800 may be referred to as an anterior-posterior or A-P cuttingguide or as a medial-lateral or M-L cutting guide. The cutting guide1800 may be used to guide a cutting tool, such as a saw blade, to cuttwo planar bone resections 20, 24 corresponding to planar surfaces 120,124 of humeral component 100, or the planar surfaces of humeralcomponents 200, 300, 400, 500, 600.

The cutting guide 1800 includes a body 1808 with a bone-facing side1809. The bone-facing side 1809 includes a planar surface 1844. Twoslots 1820, 1824 extend obliquely through the cutting guide 1800,corresponding to the relative arrangement of planar surfaces 120, 124 ofhumeral component 100, or the planar surfaces of humeral components 200,300, 400, 500, 600. The slots 1820, 1824 may intersect at the planarsurface 1844. One or more holes 1816 may extend through the cuttingguide 1800 near opposing apices or ends of the body 1808 to receivefasteners 1890, 1892 to fix the cutting guide 1800 to the humeral headprior to making any bone resections; two converging holes 1816, 1846 areshown. A central hole 1818 may extend through the cutting guide 1800 toreceive pin 900.

Referring to FIGS. 14A-14B, a cutting guide 1900 and two fasteners 1990,1992 are shown in an operative arrangement. The cutting guide 1900 maybe referred to as an anterior-posterior or A-P cutting guide or as amedial-lateral or M-L cutting guide. The cutting guide 1900 may be usedto guide a cutting tool, such as a saw blade, to cut two planar boneresections 20, 24 corresponding to planar surfaces 120, 124 of humeralcomponent 100, or the planar surfaces of humeral components 200, 300,400, 500, 600.

The cutting guide 1900 includes a shaft 1902 which extends between aproximal handle 1904 and a distal working portion 1906. The distalworking portion 1906 may be releasably or permanently coupled to theshaft 1902. The distal working portion 1906 includes the followingfeatures, which may be substantially similar to, or the same as, thecorresponding features of the cutting guide 1800: body 1908; bone-facingside 1909; planar surface 1944; slots 1920, 1924; and converging holes1916, 1946. The slots 1920, 1924 extend obliquely through the cuttingguide 1900, corresponding to the relative arrangement of planar surfaces120, 124 of humeral component 100, or the planar surfaces of humeralcomponents 200, 300, 400, 500, 600. The slots 1920, 1924 may intersectat the planar surface 1944. A central socket or hole 1918 may receiveshaft 1902.

Referring to FIGS. 15A-15B, a cutting guide 2000, pin 900, and fourfasteners 2090, 2092, 2094, 2096 are shown in an operative arrangement.The cutting guide 2000 may be referred to as a modularanterior-posterior or A-P cutting guide, or as a modular medial-lateralor M-L cutting guide. The cutting guide 2000 may be used to guide acutting tool, such as a saw blade, to cut two planar bone resections 20,24 corresponding to planar surfaces 120, 124 of humeral component 100,or the planar surfaces of humeral components 200, 300, 400, 500, 600.

The cutting guide 2000 includes a first body 2008 with a bone-facingside 2009. The bone-facing side 2009 includes a planar surface 2044. Aslot 2020 extends obliquely through the first body 2008, correspondingto the planar surface 120 of humeral component 100, or the planarsurface of humeral components 200, 300, 400, 500, 600. One or more holes2016 may extend through the first body 2008 near opposing apices or endsof the body to receive fasteners 2090, 2092 to fix the first body 2008to the humeral head prior to making any bone resections; two convergingholes 2016, 2046 are shown. A central hole 2018 may extend through thefirst body 2008 to receive pin 900. The first body 2008 includes aprotrusion 2010 which extends from the first body next to the slot 2020.The protrusion 2010 may have a rectangular, notched, dovetail, or othercross sectional shape typical of a guide rail. A window 2011 or loopextends from the first body opposite the slot 2020.

The cutting guide 2000 includes a rectangular second body 2012 with aslot 2014 that is complementary to the protrusion 2010 and sized for aclearance fit. The slot 2014 slidingly receives the protrusion 2010. Thesecond body 2012 includes a fastener 2017 which locks the second body tothe protrusion 2010 at a desired location. A slot 2024 extends throughthe second body. When the second body 2012 is operatively assembled tothe first body 2008 and the cutting guide 2000 is secured to a humeralhead, slot 2024 corresponds to the planar surface 124 of humeralcomponent 100, or the planar surface of humeral components 200, 300,400, 500, 600. One or more holes 2046 may extend through the second body2012 to receive fasteners 2094, 2096 to fix the second body to thehumerus prior to making any bone resections; three diverging holes 2046,2047, 2048 are shown.

Referring to FIG. 16, a cutting guide 2100, pin 900, and four fasteners2090, 2092, 2094, 2096 are shown in an operative arrangement. Thecutting guide 2100 may be referred to as a modular anterior-posterior orA-P cutting guide or as a modular medial-lateral or M-L cutting guide.The cutting guide 2100 may be used to guide a cutting tool, such as asaw blade, to cut two planar bone resections 20, 24 corresponding toplanar surfaces 120, 124 of humeral component 100, or the planarsurfaces of humeral components 200, 300, 400, 500, 600.

The cutting guide 2100 includes a shaft 2102 which extends between aproximal handle 2104 and a distal working portion 2106. The workingportion 2106 includes a first body 2108 and a rectangular second body2112. The first body 2108 includes the following features, which may besubstantially similar to, or the same as, the corresponding features ofthe first body a 2008: bone-facing side 2109; planar surface 2144; slot2120; converging holes 2116, 2146; protrusion 2110; and window 2111 orloop. A central socket or hole 2118 may receive shaft 2102. The secondbody 2112 includes the following features, which may be substantiallysimilar to, or the same as, the corresponding features of the secondbody 2012: slot 2114; fastener 2116; slot 2124; holes 2146, 2147, 2148.

Referring to FIGS. 17A-17C, a cutting guide 2300 and three fasteners2390, 2392, 2394 are shown in an operative arrangement. The cuttingguide 2300 may be referred to as a cut and drill guide or as asuperior-inferior or S-I cutting guide. The cutting guide 2300 may beused to guide a cutting tool, such as a saw blade, to cut two planarbone resections 22, 26 corresponding to planar surfaces 122, 126 ofhumeral component 100, or the planar surfaces of humeral components 200,300, 400, 500, 600. The cutting guide 2300 may also be used to guide acutting tool, such as a drill or reamer, to cut bone holes 28, 30, 32corresponding to anchoring elements 128, 130, 132 of humeral component100, or the anchoring elements of humeral components 200, 300, 400, 500,600.

The cutting guide 2300 includes a body 2308 with a bone-facing side2309. The bone-facing side 2309 includes intersecting planar surfaces2320, 2324. Three holes 2328, 2330, 2332 extend lengthwise through thecutting guide 2300, corresponding to the relative arrangement ofanchoring elements 128, 130, 132 of humeral component 100, or theanchoring elements of humeral components 200, 300, 400, 500, 600. Afourth hole 2334 may be included in the cutting guide 2300,corresponding to anchoring elements 434, 534, 634. Two slots 2322, 2326extend obliquely through the cutting guide 2300, corresponding to therelative arrangement of planar surfaces 122, 126 of humeral component100, or the planar surfaces of humeral components 200, 300, 400, 500,600. One or more holes 2316 may extend through the cutting guide 2300near opposing apices or ends of the body 2308 to receive fasteners 2392,2394 to fix the cutting guide 2300 to the humeral head prior to makingany bone resections; two converging holes 2316, 2346 are shown. Acentral hole 2318 may extend through the cutting guide 2300 to receivefastener 2390. Fastener 2390 may be countersunk or otherwise recessedinto the cutting guide 2300 to avoid occluding the slots 2322, 2326.Cutting guide 2300 may be secured by fastener 2390 alone, by fasteners2392, 2394, by any two of fasteners 2390, 2392, 2394, or by all threefasteners.

Referring to FIG. 18, a cutting guide 2400 and two fasteners 2492, 2494are shown in an operative arrangement. The cutting guide 2400 may bereferred to as a cut and drill guide or as a superior-inferior or S-Icutting guide. The cutting guide 2400 may be used to guide a cuttingtool, such as a saw blade, to cut two planar bone resections 22, 26corresponding to planar surfaces 122, 126 of humeral component 100, orthe planar surfaces of humeral components 200, 300, 400, 500, 600. Thecutting guide 2400 may also be used to guide a cutting tool, such as adrill or reamer, to cut bone holes 28, 30, 32 corresponding to anchoringelements 128, 130, 132 of humeral component 100, or the anchoringelements of humeral components 200, 300, 400, 500, 600.

The cutting guide 2400 includes a shaft 2402 which extends between aproximal handle 2404 and a distal working portion 2406. The distalworking portion 2406 may be releasably or permanently coupled to theshaft 2402 by threads or by releasable connection mechanisms. The distalworking portion 2406 includes the following features, which may besubstantially similar to, or the same as, the corresponding features ofthe cutting guide 2300: body 2408; bone-facing side 2409; intersectingplanar surfaces 2420, 2424 (not visible in FIG. 18); holes 2428, 2430,2432, 2434; slots 2422, 2426; and converging holes 2416, 2446. The slots2422, 2426 extend obliquely through the cutting guide 2400,corresponding to the relative arrangement of planar surfaces 122, 126 ofhumeral component 100, or the planar surfaces of humeral components 200,300, 400, 500, 600. A central socket or hole 2418 may receive shaft2402.

Referring to FIGS. 19A-19B, a cutting guide 2500 and three fasteners2590, 2592, 2594 are shown in FIG. 19B in an operative arrangement. Thecutting guide 2500 may be referred to as a cut and drill guide. Thecutting guide 2500 may be used to guide a cutting tool, such as a sawblade, to cut three planar bone resections 62, 64, 66 corresponding toplanar surfaces 762, 764, 766 of humeral component 700, or planarsurfaces 862, 864, 866 of humeral component 800. The cutting guide 2500may also be used to guide a cutting tool, such as a drill or reamer, tocut bone holes 68, 70, 72 corresponding to anchoring elements 768, 770,772 of humeral component 700, or anchoring elements 868, 870, 872 ofhumeral component 800.

The cutting guide 2500 includes a star-shaped body 2508 with abone-facing side 2509 which includes a planar surface 2544. Three holes2568, 2570, 2572 extend lengthwise through the cutting guide 2500,corresponding to the relative arrangement of anchoring elements 768,770, 772 of humeral component 700, or anchoring elements 868, 870, 872of humeral component 800. Three slots 2562, 2564, 2566 extend obliquelythrough the cutting guide 2500, corresponding to the relativearrangement of planar surfaces 762, 764, 766 of humeral component 700,or planar surfaces 862, 864, 866 of humeral component 800. One or moreholes 2516 may extend through a central portion of the cutting guide2500 to receive fasteners 2590, 2592, 2594 to fix the cutting guide 2500to the humeral head prior to making any bone resections or holes; threeskew holes 2546, 2547, 2548 are shown. The fasteners 2590, 2592, 2594may be countersunk or otherwise recessed into the cutting guide 2500 toavoid occluding the slots 2562, 2564, 2566. A central hole 2518 mayextend through the cutting guide 1800 to receive pin 900.

Referring to FIGS. 20A-20B, a proximal humerus 2 includes a humeral head4. Referring to FIGS. 21A-26B, a method of preparing a proximal humerusfor implantation of a humeral component 100, 200, 300, 400, 500, 600 mayinclude some or all of the steps of cutting a first planar boneresection 20 to remove a posterior aspect of the humeral head 4; cuttinga second planar bone resection 22 to remove an inferior aspect of thehumeral head 4; cutting a third planar bone resection 24 to remove ananterior aspect of the humeral head 4; cutting a fourth planar boneresection 26 to remove a superior aspect of the humeral head 4; cuttinga first bone hole 28 in an inferior aspect of the humeral head 4;cutting second bone hole 30 in an anterior aspect of the humeral head 4;cutting a third bone hole 32 in a posterior aspect of the humeral head4; and cutting a conical bone resection 74 on the humeral head 4 (asshown in FIG. 42). The steps may be performed in any order, andadditional steps may be performed.

With continued reference to FIGS. 21A-26B, with brief reference to FIGS.12A-12J, another method of preparing a proximal humerus for implantationof a humeral component 100, 200, 300, 400, 500, 600 may include some orall of the steps of placing the bone-facing side 1609 of the cuttingguide 1600 against an intact humeral head 4; aligning the cutting guide1600 in a desired orientation relative to the intact proximal humeralanatomy so that the projections 1656, 1657, 1658 contact the humeralhead; securing the cutting guide 1600 to the proximal humerus by drivingat least one pin through any of the holes 1616, 1646, 1647, 1648, 1649,1650, 1651, 1652, 1653, 1654; cutting four planar bone resections 20,22, 24, 26 by actuating a saw through each slot 1620, 1622, 1624, 1626;cutting three bone holes 28, 30, 32 by actuating a drill through eachhole 1628, 1630, 1632; removing the pins, the cutting guide 1600, andbone fragments or debris; and optionally cutting a conical boneresection 74 with conical reamer 1500.

Additional methods of preparing a proximal humerus for implantation of ahumeral component may include some or all of the steps of establishing ahumeral head axis; cutting anterior and posterior planar boneresections; cutting superior and inferior planar bone resections; andcutting bone holes. Each step is described below as a separate method.

Referring to FIGS. 27-29, with brief reference to FIGS. 9A-9B, a methodof establishing a humeral head axis 6 may include some or all of thesteps of placing the bone-facing side 1020 of the template 1000 againstan intact humeral head 40, which is shown in simplified form as ahemisphere; aligning the humeral shaft extension 1112 of the alignmentguide 1100 with the humeral shaft; aligning the articular bar 1114 ofthe alignment guide 1100 with the articular margin of the humeral head40; aligning the template 1000 in a desired orientation relative to theintact proximal humeral anatomy so that the projections 1024, 1026, 1028contact the humeral head 40, wherein aligning the template 1000 mayinclude aligning the shaft 1002 parallel with the post 1116; driving thepin 900 through the cannulation 1030 and into the humeral head 40; andremoving the template 1000 and alignment guide 1100. FIG. 29 shows thesimplified humeral head 40 with a central bone hole 18 created bydriving the pin 900 into the humeral head 40. The humeral head axis 6 isthe central longitudinal axis of the hole 18, and may be normal to acentral portion of the intact articular surface of the humeral head 40,or parallel to the humeral neck axis.

Referring to FIGS. 30 and 31, with brief reference to FIGS. 10A-10B, amethod of cutting a planar bone resection 44 may occur after the methodof establishing the humeral head axis 6, and may include some or all ofthe steps of inserting the pin 900 into the cannulation 1430 of theplanar reamer 1400; advancing the planar reamer 1400 over the pin 900 tocontact the humeral head 40; cutting the planar bone resection 44 byactuating the planar reamer 1400 until the continuous smooth planarsurface 1434, or the inner edge 1436 of the surface, contacts thehumeral head to stop further bone removal by the planar reamer 1400; andremoving the planar reamer. FIG. 31 shows the simplified humeral head 40with the planar bone resection 44 around the bone hole 18. The planarbone resection 44 is normal to the humeral head axis 6.

Referring to FIGS. 32 and 35, with brief reference to FIGS. 13A-14, amethod of cutting anterior and posterior planar bone resections 20, 24may occur after the method of cutting the planar bone resection 44, andmay include some or all of the steps of inserting the pin 900 into thecentral hole 1818 of the cutting guide 1800; advancing the cutting guide1800 over the pin 900 to contact the humeral head 40, wherein the planarsurface 1844 contacts the planar bone resection 44; securing the cuttingguide 1800 to the humeral head 40 by driving at least one fastener 1890,1892 through any of the holes 1816, 1846; removing the pin 900; cuttingtwo planar bone resections 20, 24 by actuating a saw through each slot1820, 1824; and removing the fastener(s) 1890, 1892 and the cuttingguide 1800. FIG. 35 shows the simplified humeral head 40 with the planarbone resections 20, 24. Cutting guide 1800 may be replaced by cuttingguide 1900 in this method, in which case the shaft 1902 and handle 1904may be used to push the distal working portion 1906 against the humeralhead 40 for added stability during one or more of the steps of securingthe cutting guide 1900 to the humeral head 40; removing the pin 900; andcutting two planar bone resections 20, 24.

Referring to FIGS. 33-35, with brief reference to FIGS. 15A-16, anothermethod of cutting anterior and posterior planar bone resections 20, 24may occur after the method of cutting the planar bone resection 44, andmay include some or all of the steps of inserting the pin 900 into thecentral hole 2018 of the first body 2008 of the cutting guide 2000;advancing the first body 2008 over the pin 900 to contact the humeralhead 40, wherein the planar surface 2044 contacts the planar boneresection 44; securing the first body 2008 to the humeral head 40 bydriving at least one fastener 2090, 2092 through any of the holes 2016,2046; removing the pin 900; inserting the protrusion 2010 into the slot2014 of the second body 2012; advancing the second body 2012 over theprotrusion 2010 to contact the humeral head 40; securing the second body2012 to the protrusion 2010 by actuating the fastener 2017; securing thesecond body 2012 to the humeral head by driving at least one fastener2094, 2096 through any of the holes 2046, 2047, 2048; cutting two planarbone resections 20, 24 by actuating a saw through each slot 2020, 2024;and removing the fastener(s) 2090, 2092, 2094, 2096 and the cuttingguide 2000. FIG. 35 shows the simplified humeral head 40 with the planarbone resections 20, 24. Cutting guide 2000 may be replaced by cuttingguide 2100 in this method, in which case the shaft 2102 and handle 2104may be used to push the first body 2008 against the humeral head 40 foradded stability during one or more of the steps of securing the firstbody 2108 to the humeral head 40; removing the pin 900; inserting theprotrusion 2110 into the slot 2114 of the second body 2112; advancingthe second body 2112 over the protrusion 2110 to contact the humeralhead 40; securing the second body 2112 to the protrusion 2110; securingthe second body 2112 to the humeral head; and cutting two planar boneresections 20, 24.

Referring to FIGS. 36-38, with brief reference to FIGS. 17A-18, a methodof cutting E superior and inferior planar bone resections 22, 26 andbone holes 28, 30, 32, 34 may occur after the method of cutting anteriorand posterior planar bone resections 20, 24, and may include some or allof the steps of placing the cutting guide 2300 against the humeral head40 so that the planar surface 2320 contacts the planar bone resection 20and the planar surface 2324 contacts the planar bone resection 24;securing the cutting guide 2300 to the humeral head 40 by driving atleast one fastener 2390, 2392, 2394 through any of the holes 2316, 2318,2346; cutting two planar bone resections 22, 26 by actuating a sawthrough each slot 2322, 2326; cutting four bone holes 28, 30, 32, 34 byactuating a drill through holes 2328, 2330, 2332, 2334; and removing thefastener(s) 2390, 2392, 2394 and the cutting guide 2300. FIG. 38 showsthe simplified humeral head 40 with the planar bone resections 22, 26and bone holes 28, 30, 32, 34. Cutting guide 2300 may be replaced bycutting guide 2400 in this method, in which case the shaft 2402 andhandle 2404 may be used to push the cutting guide 2400 against thehumeral head 40 for added stability during one or more of the steps ofsecuring the cutting guide 2300 to the humeral head 40; cutting twoplanar bone resections 22, 26; and cutting four bone holes 28, 30, 32,34.

Referring to FIGS. 39-40, with brief reference to FIGS. 19A-19B, amethod of cutting inferior, antero-superior, and postero-superior planarbone resections 64, 62, 66 and bone holes 70, 68, 72 may occur after themethod of cutting the planar bone resection 44, and may include some orall of the steps of inserting the pin 900 into the central hole 2518 ofthe cutting guide 2500; advancing the cutting guide 2500 over the pin900 to contact the humeral head 4, wherein the planar surface 2544contacts the planar bone resection 44; securing the cutting guide 2500to the humeral head 4 by driving at least one fastener 2590, 2592, 2594through any of the holes 2546, 2547, 2548; removing the pin 900; cuttingthree planar bone resections 62, 64, 66 by actuating a saw through holes2562, 2564, 2566; cutting three bone holes 68, 70, 72 by actuating adrill through each hole 68, 70, 72; and removing the cutting guide 2500and fastener(s) 2590, 2592, 2594. FIG. 40 shows the humeral head 4 withthe planar bone resections 62, 64, 66 and bone holes 68, 70, 72.

Referring to FIGS. 41-42, with brief reference to FIGS. 11A-11B, amethod of cutting a conical bone resection 74 may occur after any of themethods of cutting planar bone resections and/or bone holes, and isillustrated as if it occurs after the method of cutting inferior,antero-superior, and postero-superior planar bone resections 64, 62, 66and bone holes 70, 68, 72. The a method of cutting the conical boneresection 74 may include some or all of the steps of inserting the pin900 into the cannulation 1530 of the conical reamer 1500; advancing theconical reamer 1500 over the pin 900 to contact the humeral head 4;cutting the conical bone resection 74 by actuating the conical reamer1500 until the planar surface 1514 contacts the humeral head to stopfurther bone removal by the conical reamer 1500, wherein the planarsurface 1514 may contact the planar surface 44; and removing the conicalreamer. FIG. 42 shows the humeral head 4 with the conical bone resection74 around the humeral head 4.

Referring to FIG. 43, humeral component 700 is shown implanted on thehumeral head 4 of FIG. 42.

The components disclosed herein may be fabricated from metals, alloys,polymers, plastics, ceramics, glasses, composite materials, orcombinations thereof, including but not limited to: PEEK, titanium,titanium alloys, commercially pure titanium grade 2, ASTM F67, Nitinol,cobalt chrome, stainless steel, ultra high molecular weight polyethylene(UHMWPE), biocompatible materials, and biodegradable materials, amongothers. Different materials may be used for different parts. Coatingsmay be present. Different materials may be used within a single part.Any component disclosed herein may be colored, coded or otherwise markedto make it easier for a user to identify the type and size of thecomponent, the setting, the function(s) of the component, and the like.

It should be understood that the present systems, kits, apparatuses, andmethods are not intended to be limited to the particular formsdisclosed. Rather, they are to cover all combinations, modifications,equivalents, and alternatives falling within the scope of the claims.

The claims are not to be interpreted as including means-plus- orstep-plus-function limitations, unless such a limitation is explicitlyrecited in a given claim using the phrase(s) “means for” or “step for,”respectively.

The term “coupled” is defined as connected, although not necessarilydirectly, and not necessarily mechanically.

The use of the word “a” or “an” when used in conjunction with the term“comprising” in the claims and/or the specification may mean “one,” butit is also consistent with the meaning of “one or more” or “at leastone.” The term “about” means, in general, the stated value plus or minus5%. The use of the term “or” in the claims is used to mean “and/or”unless explicitly indicated to refer to alternatives only or thealternative are mutually exclusive, although the disclosure supports adefinition that refers to only alternatives and “and/or.”

The terms “comprise” (and any form of comprise, such as “comprises” and“comprising”), “have” (and any form of have, such as “has” and“having”), “include” (and any form of include, such as “includes” and“including”) and “contain” (and any form of contain, such as “contains”and “containing”) are open-ended linking verbs. As a result, a method ordevice that “comprises,” “has,” “includes” or “contains” one or moresteps or elements, possesses those one or more steps or elements, but isnot limited to possessing only those one or more elements. Likewise, astep of a method or an element of a device that “comprises,” “has,”“includes” or “contains” one or more features, possesses those one ormore features, but is not limited to possessing only those one or morefeatures. Furthermore, a device or structure that is configured in acertain way is configured in at least that way, but may also beconfigured in ways that are not listed.

In the foregoing Detailed Description, various features are groupedtogether in several examples for the purpose of streamlining thedisclosure. This method of disclosure is not to be interpreted asreflecting an intention that the examples of the invention require morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive subject matter lies in less than allfeatures of a single disclosed example. Thus, the following claims arehereby incorporated into the Detailed Description, with each claimstanding on its own as a separate example.

1. An arthroplasty implant to replace at least a portion of an articularhead of a bone for joint arthroplasty, comprising: a convex articularsurface; and a bone-facing side opposite the articular surface, whereinthe bone-facing side comprises a socket comprising first and second sidewalls on opposite sides of the socket, wherein the first and second sidewalls intersect each other to form an edge that extends between firstand second ends; wherein the first and second side walls intersect thearticular surface to establish an articular margin of the implant;wherein the socket comprises a maximum depth measured from the articularmargin, wherein the edge lies along the maximum depth of the socket. 2.The arthroplasty implant of claim 1, wherein when the arthroplastyimplant is implanted to replace a portion of a humeral head, the edgeextends along a superior-inferior direction, the first side wall coversan anterior aspect of the humeral head, and the second side wall coversa posterior aspect of the humeral head.
 3. The arthroplasty implant ofclaim 1, wherein the socket comprises third and fourth side walls onopposite sides of the socket between the first and second side walls,wherein a total area of the third side wall is less than a total area ofthe fourth side wall.
 4. The arthroplasty implant of claim 3, whereinwhen the arthroplasty implant is implanted to replace a portion of ahumeral head, the edge extends along a superior-inferior direction, thefirst side wall covers an anterior aspect of the humeral head, thesecond side wall covers a posterior aspect of the humeral head, thethird side wall covers a superior aspect of the humeral head, and thefourth side wall covers an inferior aspect of the humeral head.
 5. Thearthroplasty implant of claim 3, wherein at least one peg protrudes fromeach of the first, second, third, and fourth side walls.
 6. Anarthroplasty implant to replace at least a portion of an articular headof a bone for joint arthroplasty, comprising: a convex articularsurface; and a concave bone-facing side opposite the articular surface,wherein the bone-facing side comprises a concave arrangement of first,second, and third planar side walls; wherein a total surface area of thefirst side wall is less than a total surface area of the second sidewall; wherein the total surface area of the second side wall is lessthan a total surface area of the third side wall.
 7. The arthroplastyimplant of claim 6, wherein when the arthroplasty implant is implantedto replace a portion of a humeral head, the first side wall covers asuperior aspect of the humeral head, the second side wall covers aninferior aspect of the humeral head, and the third side wall covers ananterior aspect of the humeral head.
 8. The arthroplasty implant ofclaim 6, wherein the concave arrangement includes a fourth planar sidewall.
 9. The arthroplasty implant of claim 8, wherein when thearthroplasty implant is implanted to replace a portion of the humeralhead, the first side wall covers a superior aspect of the humeral head,the second side wall covers an inferior aspect of the humeral head, thethird side wall covers an anterior aspect of the humeral head, and thefourth side wall covers a posterior aspect of the humeral head.
 10. Thearthroplasty implant of claim 8, wherein a total surface area of thethird side wall is equal to a total surface area of the fourth sidewall.
 11. An arthroplasty implant to replace at least a portion of anarticular head of a bone for joint arthroplasty, comprising: a convexarticular surface that is spherical, ellipsoidal, or ovoid; and abone-facing side opposite the articular surface, wherein the bone-facingside comprises a socket comprising first and second side walls onopposite sides of the socket, wherein the first side wall is a differentsize than the second side wall.
 12. The arthroplasty implant of claim11, wherein the first side wall is smaller than the second side wall.13. The arthroplasty implant of claim 12, wherein when the arthroplastyimplant is implanted to replace a portion of a humeral head, the firstside wall covers a superior aspect of the humeral head and the secondside wall covers an inferior aspect of the humeral head.
 14. Thearthroplasty implant of claim 12, wherein the socket comprises third andfourth side walls on opposite sides of the socket between the first andsecond side walls, wherein the third and fourth side walls intersecteach other to form an interior corner.
 15. The arthroplasty implant ofclaim 14, wherein when the arthroplasty implant is implanted to replacea portion of a humeral head, the first side wall covers a superioraspect of the humeral head, the second side wall covers an inferioraspect of the humeral head, the third side wall covers an anterioraspect of the humeral head, the fourth side wall covers a posterioraspect of the humeral head, and the interior corner extends along asuperior-inferior direction between a superior end and an inferior end.16. An arthroplasty implant to replace at least a portion of anarticular head of a bone for joint arthroplasty, comprising: a convexarticular surface; and a concave bone-facing side opposite the articularsurface, wherein the bone-facing side comprises a concave arrangement ofside walls; wherein the implant comprises a superior portion, aninferior portion, and an overall S-I dimension along a superior-inferiordirection, wherein the superior and inferior portions are distinguishedfrom each other along a boundary line centered in the overall S-Idimension and extending along an anterior-posterior direction; wherein atotal surface area of the bone-facing side of the superior portion isless than a total surface area of the bone-facing side of the inferiorportion.
 17. The arthroplasty implant of claim 16, wherein a total areaof the articular surface of the superior portion is less than a totalarea of the articular surface of the inferior portion.
 18. Thearthroplasty implant of claim 16, wherein the concave arrangementcomprises a first side wall in the superior portion and an oppositesecond side wall in the inferior portion, wherein the first side wall issmaller than the second side wall.
 19. The arthroplasty implant of claim18, wherein the concave arrangement comprises a third side wall and anopposite fourth side wall, wherein the third and fourth walls are ofequal size.
 20. The arthroplasty implant of claim 19, wherein when thearthroplasty implant is implanted to replace a portion of a humeralhead, the first side wall covers a superior aspect of the humeral head,the second side wall covers an inferior aspect of the humeral head, thethird side wall covers an anterior aspect of the humeral head, and thefourth side wall covers a posterior aspect of the humeral head.